window.URL = window.URL || window.webkitURL;
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;

var HZRecorder = function (stream, config) {
    config = config || {};
    config.sampleBits = config.sampleBits || 8; //采样数位 8, 16  
    config.sampleRate = config.sampleRate || (44100 / 6); //采样率(1/6 44100)  


    //创建一个音频环境对象  
    var audioContext = window.AudioContext || window.webkitAudioContext;
    var context = new audioContext();

    //将声音输入这个对像  
    var audioInput = context.createMediaStreamSource(stream);

    //设置音量节点  
    var volume = context.createGain();
    audioInput.connect(volume);

    context.onstatechange = function () {
        console.log("state", context.state);
    }
    //创建缓存，用来缓存声音  
    var bufferSize = 4096;
    // 创建声音的缓存节点，createScriptProcessor方法的  
    // 第二个和第三个参数指的是输入和输出都是双声道。  
    var recorder = context.createScriptProcessor(bufferSize, 2, 2);

    var audioData = {
        size: 0 //录音文件长度  
            ,
        buffer: [] //录音缓存  
            ,
        inputSampleRate: context.sampleRate //输入采样率  
            ,
        inputSampleBits: 16 //输入采样数位 8, 16  
            ,
        outputSampleRate: config.sampleRate //输出采样率  
            ,
        oututSampleBits: config.sampleBits //输出采样数位 8, 16  
            ,
        input: function (data) {
            this.buffer.push(new Float32Array(data));
            this.size += data.length;
        },
        compress: function () { //合并压缩  
            //合并  
            var data = new Float32Array(this.size);
            var offset = 0;
            for (var i = 0; i < this.buffer.length; i++) {
                data.set(this.buffer[i], offset);
                offset += this.buffer[i].length;
            }
            //压缩  
            var compression = parseInt(this.inputSampleRate / this.outputSampleRate);
            var length = data.length / compression;
            var result = new Float32Array(length);
            var index = 0,
                j = 0;
            while (index < length) {
                result[index] = data[j];
                j += compression;
                index++;
            }
            return result;
        },
        encodeWAV: function () {
            var sampleRate = Math.min(this.inputSampleRate, this.outputSampleRate);
            var sampleBits = Math.min(this.inputSampleBits, this.oututSampleBits);
            var bytes = this.compress();
            var dataLength = bytes.length * (sampleBits / 8);
            var buffer = new ArrayBuffer(44 + dataLength);
            var data = new DataView(buffer);

            var channelCount = 1; //单声道  
            var offset = 0;

            var writeString = function (str) {
                for (var i = 0; i < str.length; i++) {
                    data.setUint8(offset + i, str.charCodeAt(i));
                }
            };

            // 资源交换文件标识符   
            writeString('ID3');
            offset += 4;
            // 下个地址开始到文件尾总字节数,即文件大小-8   
            data.setUint32(offset, 36 + dataLength, true);
            offset += 4;
            // WAV文件标志  
            writeString('MPEG');
            offset += 4;
            // 波形格式标志   
            writeString('fmt ');
            offset += 4;
            // 过滤字节,一般为 0x10 = 16   
            data.setUint32(offset, 16, true);
            offset += 4;
            // 格式类别 (PCM形式采样数据)   
            data.setUint16(offset, 1, true);
            offset += 2;
            // 通道数   
            data.setUint16(offset, channelCount, true);
            offset += 2;
            // 采样率,每秒样本数,表示每个通道的播放速度   
            data.setUint32(offset, sampleRate, true);
            offset += 4;
            // 波形数据传输率 (每秒平均字节数) 单声道×每秒数据位数×每样本数据位/8   
            data.setUint32(offset, channelCount * sampleRate * (sampleBits / 8), true);
            offset += 4;
            // 快数据调整数 采样一次占用字节数 单声道×每样本的数据位数/8   
            data.setUint16(offset, channelCount * (sampleBits / 8), true);
            offset += 2;
            // 每样本数据位数   
            data.setUint16(offset, sampleBits, true);
            offset += 2;
            // 数据标识符   
            writeString('data');
            offset += 4;
            // 采样数据总数,即数据总大小-44   
            data.setUint32(offset, dataLength, true);
            offset += 4;
            // 写入采样数据   
            if (sampleBits === 8) {
                for (var i = 0; i < bytes.length; i++, offset++) {
                    var s = Math.max(-1, Math.min(1, bytes[i]));
                    var val = s < 0 ? s * 0x8000 : s * 0x7FFF;
                    val = parseInt(255 / (65535 / (val + 32768)));
                    data.setInt8(offset, val, true);
                }
            } else {
                for (var i = 0; i < bytes.length; i++, offset += 2) {
                    var s = Math.max(-1, Math.min(1, bytes[i]));
                    data.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true);
                }
            }

            return new Blob([data], {
                type: 'audio/mp3'
            });
        }
    };

    //开始录音  
    this.start = function () {
        audioInput.connect(recorder);
        recorder.connect(context.destination);
    };

    //停止  
    this.stop = function () {
        recorder.disconnect();
        //清理缓存音频
        console.log("stoped", audioData.buffer.length)
        return audioData.buffer.length;
    };

    //获取音频文件  
    this.getBlob = function () {
        var time = this.stop();
        return {
            duration: time,
            blob: audioData.encodeWAV(),
        };
    };

    this.clear = function () {
        audioData.buffer = [];
    }

    //回放  
    this.play = function (audio, blob) {
        blob = blob || this.getBlob().blob;
        audio.src = window.URL.createObjectURL(blob);
    };



    //音频采集  
    recorder.onaudioprocess = function (e) {
        audioData.input(e.inputBuffer.getChannelData(0));
        //record(e.inputBuffer.getChannelData(0));  
    };

};
//抛出异常  
HZRecorder.throwError = function (message) {
    console.error(message);
};
//是否支持录音  
HZRecorder.canRecording = !!navigator.getUserMedia;
//获取录音机  
HZRecorder.get = function (callback, config) {
    HZRecorder.throwError = config && config.error || HZRecorder.throwError;
    if (callback) {
        if (navigator.getUserMedia) {
            navigator.getUserMedia({
                    audio: true
                } //只启用音频  
                ,
                function (stream) {
                    var rec = new HZRecorder(stream, config);
                    callback(rec);
                },
                function (error) {
                    switch (error.code || error.name) {
                        case 'PERMISSION_DENIED':
                        case 'PermissionDeniedError':
                            HZRecorder.throwError('用户拒绝提供信息。');
                            break;
                        case 'NOT_SUPPORTED_ERROR':
                        case 'NotSupportedError':
                            HZRecorder.throwError('浏览器不支持录音功能。');
                            break;
                        case 'MANDATORY_UNSATISFIED_ERROR':
                        case 'MandatoryUnsatisfiedError':
                            HZRecorder.throwError('无法发现指定的硬件设备。');
                            break;
                        default:
                            HZRecorder.throwError('无法打开麦克风。异常信息:' + (error.code || error.name));
                            break;
                    }
                });
        } else {
            HZRecorder.throwErr('浏览器不支持录音功能。');
            return;
        }
    }
};
export { HZRecorder };